WetSpass-Based Study of the Effects of Urbanization on the Water Balance Components at Regional and Quadrat Scales in Beijing, China

Abstract

Abstract:China is the largest country in terms of population and its booming urbanization has exerted negative effects on ground-surface hydrological processes at different spatial scales, land-use types, and water balance, such as surface runoff, groundwater recharge, and evapotranspiration. However, it is not yet well understood as to how the modifications of the spatial patterns of landscapes affect the water balance on a regional scale. In this study, the water and energy transfer among soil, plants, and atmosphere (WetSpass) model was applied to evaluate the urbanization effects on the water balance on a regional scale by using Beijing as the case city for this current study. The relationships among impervious surfaces, landscape pattern indices, and water balance components were also quantified. Results indicated built-up land in 2012 was 673 km 2 larger than it in 2000, mostly converted from croplands. WetSpass model also indicated the variation rates of annual average surface runoff, evapotranspiration and groundwater recharge were 7%, 0.4% and −2% in the whole Beijing area, while they reached 52%, 6% and −24% in the urban area of Beijing from 2000 to 2012, respectively. At a city scale, four districts-Dongcheng, Xicheng, Chaoyang, and Haidian-were characterized by higher impervious percentage, as reflected by lower groundwater recharge and higher surface runoff than other districts. At quadrat scale, however, groundwater recharge (surface runoff) was negatively (positively) correlated with impervious percentages. For landscape indices, the Aggregation Index was positively correlated with surface runoff and negatively correlated with groundwater recharge while Patch Density Index, Splitting Index, Patch Richness Density Index, and Shannon's Diversity Index presented opposite relationships. The results of this study can help to develop human knowledge about the impacts of urbanization on hydrological cycles on a regional scale.

Spatiotemporal Dynamics of Water Yield Service and Its Response to Urbanisation in the Beiyun River Basin, Beijing

“…According to the obtained meteorological data, the average annual precipitation of the Beiyun River Basin increased from 428.88 mm in 2000 to 509.11 mm in 2010, with a growth rate of 18.7%, and the average temperature for the corresponding year decreased from 12.1 • C to 11.5 • C. The climate change directly influenced the evapotranspiration and accumulation of precipitation and indirectly influenced the water yield. When interacting with other factors, such as CL, GDP, POP, the explanatory power became much stronger than that of a single factor, and this result is consistent with the findings of research on the impacts of urbanisation and associated factors on ecosystem services [43], in which the explanatory power of the interaction of any two socioeconomic or biophysical factors on ecosystem services was greater than that of a single factor. Additionally, the results of Geo-detector confirmed the conclusion that the effect of urbanisation on ecosystem services strongly depends on natural conditions [49].…”

“…The temporal and spatial characteristics of landscape pattern changes could reflect the impacts of urbanisation on ecological situations, and the ecological consequences of urbanisation can be assessed by applying landscape metrics to describe and analyse the dynamic changes of regional landscapes [39][40][41]. Referring to previous studies on urbanisation [42][43][44], changes in landscape patterns of the Beiyun River Basin were represented by five landscape indexes, including patch richness density (PRD), Shannon's diversity index (SHDI), patch density (PD), aggregation index (AI) and splitting index (SPLIT). Among them, PRD and SPLIT could reflect the fragmentation information.…”

Water Bacterial and Fungal Community Compositions Associated with Urban Lakes, Xi’an, China

“…In the past few decades, an increasing number of man-made urban lakes used for recreation have been built around city parks in order to increase the quality of the living environment for citizens [ 2 , 3 ]. Recently, urbanization has been improved due to the rapid industrialization in developing countries [ 4 ]. However, numerous quantities of pollutants from industrial and human activities are frequently discharged into the lakes [ 1 , 5 ].…”

“…However, numerous quantities of pollutants from industrial and human activities are frequently discharged into the lakes [ 1 , 5 ]. Therefore, urbanization has a detrimental influence on the water body through pollution discharge and contribution to climate change [ 4 , 6 ]. Interestingly, Xu et al [ 6 ] studied the relationship between urbanization-related factors and bacterial communities in the soil of urban park.…”

Hydrological Modeling to Assess the Efficiency of Groundwater Replenishment through Natural Reservoirs in the Hungarian Drava River Floodplain

“…The spatial distribution of groundwater recharge and evapotranspiration were estimated by the WetSpass-M model [71]. The WetSpass model has been applied to assess water balance components in different regions around the world [72][73][74][75][76][77]. The WetSpass model considers the spatial distribution of the soil, land use, slope, groundwater depth, and the meteorological data of every grid cell are divided into four fractions (vegetated, bare soil, open water surface).…”